As is known in the art, a Radio Frequency (RF) Transistor Amplifiers have a wide range of applications, in many of these applications it is highly desirable to reduce the power required to operate these amplifiers. As is also known, one type of RF amplifier includes a Group III-V semiconductor, depletion mode, Field Effect Transistor (FET), indicted as “R F FET” in FIG. 1, arranged in a common source configuration requiring operation with both a positive voltage supply (+VDD) and a ground potential, as shown in FIG. 1. More particularly, the drain of the RF FET is coupled to +VDD, the source is coupled to ground, and the gate has a rectifying (diode) Schottky contact with the III-V semiconductor. The gate is fed by an RF input signal. The input RF signal at the gate is amplified by the RF FET and the amplified RF signal appears at the drain of the RF FET.
As is also known in the art, the RF FET gate of the RF amplifier requires a quiescent DC bias voltage in addition to quiescent DC gate current. This DC bias voltage comes from a DC voltage source with the amount of current supplied to the gate (a gate current) typically being a function of the RF signal fed to the gate of the RF FET. One such DC voltage source is shown in FIG. 1. Here, the DC voltage source is a current mirror bias network having a source follower (SF) transistor circuit connected between the positive supply +VDD and a negative supply −VSS. More particularly, in response to the RF input signal at the gate of the RF FET, the gate of the common source configured RF FET must be supplied the current, commonly known as gate current, from the source follower section of the current mirror bias network. This gate current supplied to the RF FET must be sufficient to supply proper amounts current for the rectifying Schottky contact gate of the RF FET.